Hectograph blanket



March 18, 1930. w. HosKlNs, JR

HECTOGRAPH BLANKET Filed July 2, 1928 Patented Mu. ,18, 1930 UNITEDSTATES PATENT OFFICE WILLIAM HOSXINS, JR., 0F CHICAGO, IITLIII'OISJ,ASSIGNOR TO DITTO INCORPORATED,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS HECTOGRAPH BLANKETApplication filed July 2,

This invention relates to hectograph sheets or blankets or similar meanswhich embody the same characteristic principles of operation.

The principal object of the present invention is to provide a hectographsheet or blanket having the customary coating of suitable material forthe absorption of ink, which will produce a large number of good coples,will not harden or dry out and which is substantially opaque whereby theink absorbed inwardly from the surface renders it visibly clean.

The use of hectograph sheets or blankets is well known for reproducingcopies of typed, written or other like matter, and is known to involvethe use of a coating usually of a mixture of glue and glycerin appliedon a backing sheet. The written matter to be reproduced is producedoriginally in a special kind of ink adapted for this use which 1sabsorbed by and maintained on the surface of the glue and glycerincoating when the sheet is pressed in contact therewith. Relatlvely largenumbers of copies may be made by placing additional sheets in contactwith the blanket which gives up the ink to produce reproductions of theoriginal thereon.

After periods of standing the glue-glycerin coating possesses acharacteristic of absorbing the ink inwardly from the surface wherebythe surface is' rendered clean and fresh and capable of reuse forproducing additional and different copies.

In order to produce good copies it is found desirable, after theoriginal has been oset on to the glue-glycerin blanket, to ascertain byinspection the quality of the offset, that is to make sure that the copyhas been accurately transferred and is in proper condition to takeadditional copies from. It is also found, however, that the ink which.has been absorbed inwardly of the surface as occasioned by former useof the blanket becomes diiused throughout the volume of the coatingmaterial, and due to the transparent nature of the glue-glycerincoating, is readily visible presenting a background similar in color tothat of the ink employed. The presence of the ink v colored backgroundrenders it very diiiicult 1928. Serial No. 290,037.

because the absorbed inkilickly forms the background against whiccontrast can be made.

no substantial It has been found desirable,therefore, to

incorporate Ain the blanket ,coating material, a pigment whichwill havesuicient hiding power to render the blanket substantially opaque and ofsuch contrasting color that the freshly inked surface will be readilyvdetectable upon inspection. This involves considerable difficulty,however, on account of the fact that many pigments or inert powderedsubstances which might be employed for this purpose tend to dilute theink absorbing medium with a consequent diminishin of the eiect andfunctiomng of the blanet, and further tend to render the coating shortor crumbly in character and to cause premature dr ing or hardeningthereof.

t has been only through long experimenting that a substance having thedesirable properties has been found, that is, having such high hidingpower that it will produce a coating substantially opaque when employedin quantities proportionall so small that its presence has substantia lyno eiiect on the properties of the blanket.

The present invention accordingly involves the use'of titanium oxidewhich is a white inert powdered substance having an extremely highhiding power. Titanium oxide is found in practice to produce whiteblankets f troduction of the titanium oxide by any desited method, itbeing found well in practice to mix it in with the glue-glycerincomposition by the use of mixing ro s, it being found that thepulverizing and mixing action of 5 the rolls produces superior results.The small amount necessary to, produce the desirable opaque character ofthe coatingl is found to have substantially no effect on t e propertiesof the blanket material and consequently rem sults in a blanket havingall of the usual dcsirable properties of hectogra h blankets plus thatof ready visibility of t e fresh im- A print on its surface.

order to better understand this invenfwgtion, reference is here made tothe accom- 44i) backing sheet and ah panying drawing which discloses ahecto- 1 gr ph roll constructed in accordance with the present inventionin Which--v Figure 1 is an enlarged cross sectional view 2o with thematerials employed indicated on the drawing, and l ?j;

Figure 2 is a perspectivegview-of-aroll. As shown in the drawing,the'coatin ofthe described kind is applied ltogthe tlexib e l'iaffll-lVing sheet in a mannerpdisclosed. :Jj It is to-be understoodffktliatitheabove disclosure is merely given byway; of example as one form of theinventiort'and is' not` to be considered as limitingthe invention in'nyf The true scope of the` invention will be aS- certained from'anunderstandngof th-0peration of advantages of the present disclosure withthe knowledge that itis one embodiment thereof. The scope of theinvention is particularly pointed out in the appended claims. Y

I claim: A 1. A hectograph blanket, i comprising, a

on `one -face thereof of the usual g l: ycerine compol sition, saidcoatingc titanium'oxide.

2. A hectografliflanketcomprising, a

backing sheet an a eating on one face -thereof the usual glue and`glycerin com osition -said coating containing substantia yfl/Z of 1% oftitanium oxide.

Signed at Chicago, Illinois, this 23rd day of J une,l 1928.

. WILLIAM HOSKINS, JR.

